All You Need to Know About the Anonymous Function in Python

All You Need to Know About the Anonymous Function in Python | Information Technology | Emeritus

Imagine you have a long list of integers and must find all the prime numbers within it. It is difficult to define a full-fledged function and check each number, especially for extensive lists. However, we can create a lambda function that takes a number (n) and applies the prime function to it. As a result, the code then filters out the composite numbers and returns prime numbers within the list. This is how the anonymous function in Python can be a valuable tool to solve various problems. But what is an anonymous function? An anonymous function in Python, also known as a lambda function, is a small, unnamed function defined using the lambda keyword. Anonymous functions make the code concise, readable, and efficient. So, let’s delve deeper into the topic and examine its benefits.

How is the Anonymous Function in Python Different From its Regular Functions?

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1. Syntax

You can define an anonymous function in Python using the lambda keyword, which is followed by parameters and an expression. In contrast, you define a regular function using the def keyword, followed by a function name, parameters, and a colon.

2. Name

Lambda functions in Python do not have an explicit name. One typically uses them for short, one-off operations, which are not reusable, whereas regular functions are reusable because they are assigned a specific name.

3. Scope

The scope of an anonymous function in Python often limits it to specific tasks. It is used inline, within other functions or expressions. On the other hand, one can define a regular function anywhere in the code and call it from any part of the program where it is visible.

4. Return

Lambda functions in Python restrict themselves to a single expression and implicitly return the result of that expression. Regular functions can contain multiple statements and can include a return statement to return a value.

ALSO READ: A Beginner’s Guide to Python: Meaning, How to Learn, and Use it

What are the Advantages of Using Anonymous Functions in Python?

There are a lot of functions in Python programming with their own set of advantages. However, only anonymous functions can offer some of the advantages listed below:


You can define small, one-line functions using lambdas without needing a separate def block. It can reduce code clutter and make the code concise, especially for simple tasks.

1. Readability

Lambdas can enhance the clarity of the code. They provide a clear and succinct representation of the operation’s performance.

2. Flexibility

Modularity is one of the key advantages of lambdas. It is easy to pass them around as arguments to other functions to create ones that adapt their behavior dynamically.

3. Efficiency

The lambdas boost efficiency in Python programming with functions like filter or map, especially for large data sets.

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How Can Anonymous Functions be Used Effectively in Python Programming?

1. Functional Programming Paradigm

Lambda functions are integral to functional programming in Python. Use them with higher-order functions such as map(), filter(), and reduce() to perform transformations, filtering, and aggregation on iterable data structures.

2. Data Transformation

The Python anonymous function is useful for transforming data structures, such as dictionaries or lists. They are useful in scenarios where there is a need for quick transformation.

3. Callbacks

Many coders use the Python anonymous function as a callback function, especially in event-driven programming or asynchronous programming paradigms.

4. Sorting and Key Functions

Use lambdas as key functions for sorting iterable objects. They can define custom sorting criteria without defining a separate function.

Are Anonymous Functions Limited to a Specific Programming Language Like Python?

An anonymous function in Python is not exclusive. They are quite common across various programming languages, serving similar purposes and characteristics. Here are a few examples: 

1. JavaScript

The coding language uses a function keyword or arrow functions (=>).

2. Java

A coder can employ lambda expressions with syntax such as (args) -> { body }in Java.

3. C++

There is an option to use lambda expressions introduced in C++11 with syntax similar to Java.

4. Haskell

It relies heavily on functions as first-class citizens, akin to functional programming, making anonymous functions ubiquitous.

5. Ruby

The coding language uses proc or lambda keywords to define anonymous functions.

In short, many languages use anonymous functions and also share similarities with Python in their usage. For instance, most languages restrict anonymous functions to a single expression. They also allow passing anonymous functions as arguments to other functions.

Can Anonymous Functions be Used in Object-Oriented Programming With Python?

The short answer is that an anonymous function in Python can be used in Object-Oriented Programming (OOP), but its role is complementary rather than central. Here’s how they fit in:

1. Class Methods

A lambda is convenient to define to perform short, specific operations within class methods. It is useful when the operation is simple and doesn’t require a separate method definition. 

2. Callback Function

Use lambdas to pass arguments to methods or constructors to serve as callback functions, especially in event-driven programming scenarios.

3. Sorting and Filtering

It is possible to use lambda functions in sorting and filtering operations within class methods, such as sorting lists of objects based on specific attributes or filtering data based on certain criteria.

While there are ways to use lambdas in OOP, it is important to remember that lambdas lack features like docstrings, introspection, and self-reference. This, therefore, makes them less suitable for complex logic or reusable functionality.

ALSO READ: Is Coding a Good Career and Will it Stay Relevant in the Future?

Anonymous functions serve as an important feature in Python and other programming languages, making them indispensable to coders. It is thus important to familiarize yourself with lambdas to future-proof your career. Emeritus offers an array of online courses designed to equip learners with practical knowledge of all programming languages out there. These courses distill complex ideas into insightful examples, complete with the latest trends. Enrol in one of Emeritus’ IT courses today and unleash your potential in the exciting world of coding!

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About the Author

Content Writer, Emeritus Blog
Mitaksh has an extensive background in journalism, focusing on various beats, including technology, education, and the environment, spanning over six years. He has previously actively monitored telecom, crypto, and online streaming developments for a notable news website. In his leisure time, you can often find Mitaksh at his local theatre, indulging in a multitude of movies.
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